Benifets of making public proofreading comments include:

Because I also check to see if anyone else has made a comment reporting the same error, it prevents the writer from getting many messages for the same correction.

When people see the comment and a polite reply from the author reporting the error has been fixed, it encourages them to report proofreading errors that they see, instead of saying silent, improving general quality of published articles.

This doesn't really apply in this case, but sometimes when a proposed correction resolves confusion generated by the error, the proofreading comment can help other readers to understand before the author responds and fixes the mistake.

I agree that due to being a distraction after the error is fixed, this is a tradeoff, and I would like to reduce that effect, perhaps a way to tag a thread as "resolved proofreading issue" that would collapse it be default or sort it to the end.